Yes, I knew that I can change column's size as you say. But I have some file (I attached one of these) showing the problem. The name shown in MP3tag is longer and complete but in J.C Media is cut after 30 characters. I tried also to change completely the name but nothing changed. With other files, with long name, there is no problem. I add another observation: the word "gläubet" is shown as "gläubet" and this happens with all the words containing German specific characters (ä, ü, ö, etc). Could you please verify? Thank you in advance.
(I reduced the dimension of the original file)